This application is based on Japanese Patent Application Nos. 11-184263 (1999) filed Jun. 29, 1999, and 2000-188401 (2000) filed Jun. 22, 2000, the contents of which are incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus which is able to perform predetermined protection treatment to the recording surface of a recorded printing medium.
2. Description of Prior Art
As an image forming apparatus, an ink-jet printing apparatus, for example, is widely used in practical applications. In the ink-jet printing apparatus, one which is known to have a protection treatment apparatus which performs protection treatment to the recording surface of the printing medium for protecting the image recorded by the printing part thereof.
The ink-jet printing apparatus provided with such a heat protection treatment apparatus, for example, as shown in Japanese Patent Application Laid-open No. 10-230589 (1998), comprises a paper feed part provided with a roll paper as a printing medium, a printing part for performing printing operation to the recording surface of the roll paper from the paper feed part, a switchback mechanism for reversing the transportation direction of a paper cut to a predetermined length after printing by the printing part so that it is transportable relative to a protection treatment apparatus disposed right beneath the printing part, a protection treatment apparatus disposed on the lower part of the enclosure of the printing apparatus for heat treating to protect the image formed on the recording surface of the paper, and a delivery part for discharging the paper delivered from the protection treatment apparatus to the outside.
The roll paper in the paper feed part, as shown in, for example, Japanese Patent Application Laid-open No. 7-237348 (1995) and Japanese Patent Application Laid-open No. 7-237348 (1995) and Japanese Patent Application Laid-open No. 8-2090 (1996), as multilayer construction comprised of a protective layer as an ink-permeable porous polymer layer or a porous resin layer which is disposed on the outermost surface layer and an ink absorption retaining layer which is disposed under the protective layer.
When ink adheres to the recording surface of such a roll paper, the ink penetrates the protective layer and reaches the ink absorption retaining layer. After that, when the printed recording surface is heat treated by the protection treatment apparatus under an applied pressure, by the heat treatment, the protective layer is changed to a flat transparent film, thereby protecting the image. Namely by this processing, the protective layer protects the ink absorption retaining layer to improve the water resistance and weather resistance of the roll paper. At this moment, moisture of the ink absorbed into the roll paper evaporates.
In an ink-jet printing apparatus provided with the above-described protection treatment apparatus, it is desirable that a roll paper having no protective layer and cut sheets, and the like are also printed as well in the same apparatus.
However, when, after the roll paper having no protective layer is printed, the printed paper is passed through the protection treatment apparatus and discharged, depending on the property differences of the paper, there may occur malfunctions such as sticking of paper in the protection treatment apparatus, jamming of the paper, or damage of the paper due to heat in the protection treatment apparatus.
In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of performing protection treatment to the recording surface of a recorded printing medium, which is able to selectively perform recording operation to a printing medium not requiring protection treatment or a printing medium requiring protection treatment, and avoid occurrence of abnormal transportation and damages due to heat of printing medium not requiring protection treatment.
In accordance with the present invention which attains the above object, there is provided an image forming apparatus comprising a common transportation passage through which each of printing media of a plurality of types is transported, a printing part disposed opposite to the common transportation passage for performing printing operation to the recording surf ace of the printing medium, a protection treatment transportation passage connected to the common transportation passage and provided with a protection treatment apparatus for performing protection treatment to the printing medium for treating an image on the recording surface printed by the printing part, a discharge transportation passage connected to the common transportation passage for discharging the printing medium printed by the printing part, a selective delivery part for delivering the printing medium printed by the printing part from the common transportation passage selectively to the protection treatment transportation passage or the discharge transportation passage, a printing medium detection part for detecting the type of the printing medium, and a control part for performing delivery operation of the recorded printing medium to the selective delivery part according to a detection output signal from the printing medium detection part and to the protection treatment transportation passage or discharge transportation passage according to the type of the printing medium.
As can be seen from the above description, with the image forming apparatus according to the present invention, the control part performs selective delivery operation of the printing medium from the common transportation passage which is printed by the printing part to the selective delivery part for selectively delivering it to the protection treatment transportation passage or the discharge passage, and to the protection treatment transportation passage or the discharge passage according to the type of the printing medium, so that selective recording operation can be performed to a printing medium not requiring protection treatment or a printing medium requiring protection treatment, and abnormal transportation in the printing medium not requiring protection treatment and damages due to heat can be avoided.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.